1. Field of the Invention
The present invention relates to an electric door lock, more particularly to an electric door lock which is operable both manually and electrically.
2. Description of the Related Art
Electric door locks are known in the art. A conventional electric door lock generally includes an electric motor with a transmission shaft coupled to a spindle which is connected operably to a latch bolt. By operating the electric motor, the spindle is rotated to move the latch bolt between locking and unlocking positions. On the other hand, a conventional manually operable door lock is known to include a lock body having a manual operating portion and a key-operated lock unit which are operable for rotating a spindle, and a latch bolt connected operably to the spindle. By operating the manual operating portion or by operating the lock unit with the corresponding key, the spindle can be rotated to move the latch bolt between locking and unlocking positions.
In Applicant""s co-pending U.S. patent application Ser. No. 09/698,540, filed on Oct. 27, 2000, there is disclosed an electric door lock that is operable both electrically and manually so as to provide added convenience to the user.
The object of the present invention is to provide an electric door lock that is operable both electrically and manually.
Accordingly, the electric door lock of the present invention includes a lock housing, a deadbolt, a manual operating member, a spindle coupling plate, a gear plate unit, a clutch unit, an electric driving motor, an electric switch unit, and a switch actuator. The deadbolt is mounted in the lock housing, and is movable between locking and unlocking positions. The manual operating member is mounted on the lock housing, and has a deadbolt operating spindle extending into the lock housing and connected operably to the deadbolt, and a manually operable rotary knob secured to one end of the spindle and disposed externally of the lock housing. The spindle coupling plate is sleeved on the spindle so as to be co-rotatable therewith. The spindle coupling plate has a first side face. The gear plate unit is sleeved rotatably on the spindle, and is disposed adjacent to the spindle coupling plate. The gear plate unit has a second side face which confronts the first side face of the spindle coupling plate. The gear plate unit further has a peripheral edge formed with a set of transmission teeth. The clutch unit is provided on the first and second side faces, and includes a plurality of ball recesses which are formed in the second side face of the gear plate unit and which are angularly displaced from each other by a predetermined angle with respect to the axis of the spindle. The clutch unit further includes a ball member provided on the spindle coupling plate, and a biasing spring for biasing the ball member to project from the first side face of the spindle coupling plate for engaging one of the ball recesses. The electric driving motor has a transmission shaft coupled to the transmission teeth of the gear plate unit. The rotary knob is operable so as to rotate the spindle by the predetermined angle about the axis of the spindle for moving the deadbolt between the locking and unlocking positions. The ball member is retracted from said one of the ball recesses and moves toward the spindle coupling plate against biasing action of the spring when the spindle is rotated to result in corresponding rotation of the spindle coupling plate relative to the gear plate unit. The ball member projects from the first side face, and extends into another one of the ball recesses when the spindle coupling plate is rotated with the spindle by the predetermined angle to align the ball member with said another one of the ball recesses. The electric driving motor is operable to drive rotation of the gear plate unit so as to cause corresponding rotation of the spindle coupling plate by virtue of the engagement between the ball member and said one of the ball recesses, thereby rotating the spindle for moving the deadbolt between the locking and unlocking positions. The electric switch unit is mounted in the housing adjacent to the spindle coupling plate, and is connected electrically to the electric driving motor. The switch actuator is provided on the spindle coupling plate for co-rotation therewith. The switch actuator projects in a radial direction with respect to the axis of the spindle, is movable with the spindle coupling plate relative to the electric switch unit, and enables the electric switch unit to control operation of the electric driving motor in a manner that the electric driving motor drives rotation of the spindle by the predetermined angle when the electric driving motor is operated.